package com.team.engine.common.view;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 生成验证码
 */
public class ValidateCode extends HttpServlet {
       
	private static final long serialVersionUID = -4874604568586961699L;

	/**
     * @see HttpServlet#HttpServlet()
     */
    public ValidateCode() {
        super();
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		this.doPost(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		 response.setContentType("image/jpeg");
	        response.setHeader("Pragma","No-cache");
	        response.setHeader("Cache-Control","no-cache");
	        response.setDateHeader("Expires", 0);       
	        HttpSession session=request.getSession();
	        // 在内存中创建图象
	        int width=100, height=40;
	        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

	        // 获取图形上下文
	        Graphics g = image.getGraphics();

	        //生成随机类
	        Random random = new Random();

	        // 设定背景色
	        g.setColor(getRandColor(200,250));
	        g.fillRect(0, 0, width, height);

	        //设定字体
	        g.setFont(new Font("Times New Roman",Font.PLAIN,18));

	        //画边框
	        //g.setColor(new Color());
	        //g.drawRect(0,0,width-1,height-1);


	        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
	        g.setColor(getRandColor(160,200));
	        for (int i=0;i<155;i++) {
	            int x = random.nextInt(width);
	            int y = random.nextInt(height);
	            int xl = random.nextInt(12);
	            int yl = random.nextInt(12);
	            g.drawLine(x,y,x+xl,y+yl);
	        }

	        // 取随机产生的认证码(4位数字)
	        StringBuilder sRand = new StringBuilder(4);
	        for (int i=0;i<4;i++){
	            String rand=String.valueOf(random.nextInt(10));
	            sRand.append(rand);
	            // 将认证码显示到图象中
	            g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
	            g.drawString(rand,13*i+20,16+i+8);
	        }

	        // 将认证码存入SESSION
	        session.setAttribute("rand",sRand.toString());
	        // 图象生效
	        g.dispose();
	        ServletOutputStream responseOutputStream =response.getOutputStream();
	        // 输出图象到页面
	        ImageIO.write(image, "JPEG", responseOutputStream);
	        
	        //以下关闭输入流！
	        responseOutputStream.flush();
	        responseOutputStream.close();
	}
	
	private Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}
	   
}
